This invention relates to corrugated bodies and more particularly to a prestressed panel and a method of constructing such panels from sheets of flexible material.
It is known to form sheets of paper into cardboard wherein a sheet of corrugated paper is glued between a pair of paper cover sheets. The process for forming the cardboard includes wrinkling the corrugated sheet between the nip of a pair of meshing corrugation rollers which permanently wrinkles the paper sheet which is thereafter sandwiched between and glued to the other sheets of paper. It is also known to form permanently corrugated metal sheets by the rolling process for use as roof structures on certain buildings and for other purposes. When paper is corrugated, since it has substantially little yield strength with no flexibility, it is quickly deformed permanently. It thus cannot be prestressed for uses where a prestressed material may be required. Metals have a very high yield strength with little or no flexibility below its yield strength and is permanently deformed when corrugated. Thus, it too is not in a prestressed condition if used in a honey comb type structure. Synthetic plastics, such as polyethylene plastics and vinyl plastics, on the other hand are generally flexible. Unless corrugating rollers are heated so as to heat and deform the plastic sheets fed thereto, these materials revert to their original shapes or fail so that they have not been utilized as corrugated panels or the like. By forming prestressed corrugated panels from synthetic plastic materials such as polyethylene or certain metals a relatively strong structure can be constructed which can have good insulating qualities for use in buildings, especially if the voids between the corrugation ridges and furrows are filled with a material having high insulating properties such as polyurethane foam.